The only kanji that fill that description are a handful of 国字; I don't think there are enough of them to justify a specific term. (Note that the Joyo List often gives only one reading for a kanji because that's the only one that's used in modern Japanese, not because it's the only one the kanji has ever had. All kanji, other than 国字, should in theory have at least 2 readings, even if some of them are rare.)

For example, 液 has only one reading (エキ), which is an on'yomi (Sino-Japanese reading). Since it has an on'yomi reading, it's not a 国字 (Japanese-made Kanji), as 国字 have only kun'yomi (Japanese reading) and never an on'yomi (which comes from China).

tehfriendlyghost Wrote:For example, 液 has only one reading (エキ), which is an on'yomi (Sino-Japanese reading). Since it has an on'yomi reading, it's not a 国字 (Japanese-made Kanji), as 国字 have only kun'yomi (Japanese reading) and never an on'yomi (which comes from China).

液 has only one Joyo-approved reading, which is the on-yomi エキ. If you look at larger Japanese dictionaries they will give you more, although most of them are obsolete or rare. My 新漢語林 has four on-yomi for 液, although it doesn't give any examples of words using the other three. It gives several kun-yomi, but doesn't give any information about when they might be used. The dictionary associated with the Kanji Kentei exam has two kun-yomi, しる and わき (both of which are in the 新漢語林). The Koujien dictionary, under the word つゆ, lists both 液 and 汁 as possible kanji that could be used to write the word.

I don't think that China actually uses them, they just got assigned on-yomi in Japan because people wanted to make compounds with them. There are even a few 国字 that only have on-yomi (according to Wikipedia).

(2015-02-18, 5:04 pm)tehfriendlyghost Wrote: For example, 液 has only one reading (エキ), which is an on'yomi (Sino-Japanese reading). Since it has an on'yomi reading, it's not a 国字 (Japanese-made Kanji), as 国字 have only kun'yomi (Japanese reading) and never an on'yomi (which comes from China).